DESCRIPTION: The principal investigator proposes to investigate the structure and intracellular trafficking of HLA class II binding peptides originating from viral and endogenous proteins during influenza infection. The objectives of the study are to: (1) characterize naturally processed influenza peptides bound to HLA class II molecules, (2) examine the trafficking and processing of cytosolic influenza proteins in the class II presentation pathway, and (3) assess the effect of influenza infection on the binding of self peptides to class II molecules.